Mercury switch



Dec. 21 1926.

R. L. KNUTSSON MERCURY SWITCH Filed Oct. 16, 1924 Patented Dec. 21, 1926.

, 1,611,594 PATENT OFFICE.

ROGER L. KNU'ISSON, OF ROCKFORD, ILLINOIS, ASSIGNOR F ONE-HALF TO EDGAR O. ALLEN, OF ROCKFORD, ILLINOIS.

MERCURY SWITCH.

Application filed October 16, 1924. Serial No. 743,952.

This invention relates to mercury switches and particularly to a switch having a construction to permitit to be readily connected to a suitable socket in order to obtain quick and easy connection thereto.

The growing demand for mercury switches in various arts has resulted in uses therefor which call for mounting a switch in a movble part, the motion of which serves to 0 actuate the switch. In such use, it is, of

course, necessary to have electrical connection thereto and frequently the character of the switch mounting makes it diflicult to secure a simple arrangement for a proper 5 and eflicient electrical connection to a switch.

It is the object of the present invention to provide a mercury switch construction adapted to permit electrical connection thereto by a plug and socket relation.

) A particular object of the invention is to provide a mercury switch capable of using a standard bayonet socket of the type employing a single central contact.

A still further object of the invention is 5 to employ a conducting material to form the casing'of the switch and thereby to provide one contact to the mercury.

A still further object of the invention is to provide a switch body having a metallic case which serves as one terminal for the switch.

In the drawings, Figure 1 indicates a switch and a standard socket in separated relation.

Fig. 2 is a longitudinal section of the switch of Fig. 1.

Fig. 3 is a cross section of the switch on the line 33 of Fig. 2.

The body of the switch consists of a tubular open-ended cylindrical casing 4 of electrically conducting substance, iron being the One end of the switch; is shown closed by a metal end 5 integral preferred material.

therewith, thus forming a fmetal thimble with one closed end. In the other end there is a plug 6 of insulating material such as fiber, or one of the synthetic resins such as bakelite. The plug fits tightly within the opening of the tubular member 4 and is provided with an overla ping flange 7, the edge of which lies flush with the outside of the casing 4, thus forming a continuously cylindrical switch body. On the interior of the casing the plug has a centrally located round ng projection 8 through the center of which a single contact 9 extends. The

contact projects from the plug to a slight extent into the interior of the casing in order to afford sufiicient surface to make contact with the globule of mercury a. At the outside of the cap or plug 6 a depression 10 is formed centrally in the material thereof into which the other end of contact 9 extends. A thin metallic washer 11 is placed in the bottom of the depression 10 over which solder 12 is placed to fill the depression, the solder tent above the fiat surface of the'plug end. Diametrically o posite pins 13 and 14 pass through the casing 4 into the plug 6 to secure the parts together and also to provide attaching means for use in the socket illustrated.

As shown in Fig. 1, the socket comprises a tubular member 15 of such size and shape that the casing l fits readily thereinto. A single spring-pressed contact 16 centrally of the socket makes contact with the solder- 12. Bayonet slots 17 and 18 of usual construction receive the pins 13 and 1 1 in a well known manner. This construction provides a quick detachable switch.

In operation the mercury flows from end to end as the switch is tilted. Upon reaching the contact end of the switch the mercury has little tendency to bounce away therefrom because of the rounded or inclined form of the projection 8. This assures a ready functioning of the switch without a preliminary cutting elf of current, which might result if the mercury should jump away from the end because of impact therewith.

The use of a metallic switch casing minimizes the danger of breakage. The conducting character of the casing permits one electrical contact to be made therethrough rather than through the socket attachment, thus adapting the switch to a well known standard single-contact socket. A furtheradvantage of the .metallic casing lies in the fact that it forms an annular contact about the central contact, thus eliminating the necessity of locating the switch with one particular side uppermost.

I claim as my invention:

1. A quick-detachable mercury switch adapted for insertioninto a bayonet-slotted socket having av single central contact, said switch comprising, in combination, a casing preferably protruding to a slight exincluding a tubular metallic member, insulating material closing one end of said metallic member, a single contact extending through said insulating member to the interior of the casing, theouter end of said contact being centrally located on the end of said insulating member and adapted for electrical connectionswith the. central contact of the socket, mercury in said casing, and a pin projecting from said casing and entering both of said members, said pin being adapted to enter thebayonet slot of the socket.

2. A nick-detachable mercury switch adapted or insertion into a bayonet-slotted socket having a single central contact, said switch comprising, in combination, a casing including a metallic thimble having a closed end integral therewith, an insulating Incmber closing the other end of said thimble, a single contact extending through said membeninto the interior of the casing, the outer end of said contact being cent-rally located on the end of said insulating member and adapted for electrical connection with the central contact of the socket,

mercury in the casing, and a pin projecting from the casing and entering said thimble and said member, said pin being adapted to enter the bayonet slot of the socket.

3. A quick-detachable mercury switch adapted for insertion into a bayonet-slotted socket having a single central contact, said switch comprising, in combination, a casing including a cylindrical tubular metallic member and an insulating plug closing one end of said member, a globule of mercury adapted to flow from end to end of said casing as the same is tilted, a single contact extending centrally through said plug, the

outer end of said contact being adapted for electrical connection with the central contact of the socket and the inner end of the contact being adapted to connect with said mercury, and two diametrically opposite pins projecting from the casing adjacent the plug end, said pins being adapted to enter the bayonet slots of the socket.

In testimony whereof, I have hereunto affixed my signature.

ROGER L. KNUTSSON. 

